The object of the proposed studies is to determine the unique aspects of craniofacial growth observed in children with various types of birth defects. Since etiologic homogeneity in these conditions cannot be assumed on the basis of phenotypic similarity, three hierarchical categories are proposed: (1) inherited metabolic, or proven cytogenetic disorders; (2) defects that show well-defined phenotypic expression, but in which inheritance factors are unclear; and (3) complex syndromes in which etiologic factors are obscure. As a model, data obtained from children with proven cytogenetic disorders will be analyzed (Turner's Syndrome). Similar data will be collected from children with other types of birth defects concurrently. This material will include: anthropometric; cephalometric and dental records; and genetic studies to determine mode of inheritance. Analysis of the data by multivariate techniques will provide a measure of prediction by determining the combination of craniofacial variables that best describes facial development in a particular craniofacial syndrome. Changes in craniofacial growth patterns that distinguish children with facial birth defects will require cumulative data. This is a longterm goal of these studies. The ultimate benefit of this work is to provide the pediatrician, reconstructive surgeon, and orthodontist with accurate growth information that will be of value in planning the type and timing of therapy for children with craniofacial birth defects.